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[73.71.40.85]) by smtp.gmail.com with ESMTPSA id n22sm5965128pfh.166.2018.11.29.19.34.30 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 29 Nov 2018 19:34:32 -0800 (PST) Received: by garbanzo.do-not-panic.com (sSMTP sendmail emulation); Thu, 29 Nov 2018 19:34:29 -0800 Date: Thu, 29 Nov 2018 19:34:29 -0800 From: Luis Chamberlain To: Brendan Higgins Cc: gregkh@linuxfoundation.org, keescook@google.com, shuah@kernel.org, joel@jms.id.au, mpe@ellerman.id.au, joe@perches.com, brakmo@fb.com, rostedt@goodmis.org, Tim.Bird@sony.com, khilman@baylibre.com, julia.lawall@lip6.fr, linux-kselftest@vger.kernel.org, kunit-dev@googlegroups.com, linux-kernel@vger.kernel.org, jdike@addtoit.com, richard@nod.at, linux-um@lists.infradead.org, daniel@ffwll.ch, dri-devel@lists.freedesktop.org, robh@kernel.org, dan.j.williams@intel.com, linux-nvdimm@lists.01.org, kieran.bingham@ideasonboard.com, frowand.list@gmail.com, knut.omang@oracle.com Subject: Re: [RFC v3 08/19] arch: um: add shim to trap to allow installing a fault catcher for tests Message-ID: <20181130033429.GK18410@garbanzo.do-not-panic.com> References: <20181128193636.254378-1-brendanhiggins@google.com> <20181128193636.254378-9-brendanhiggins@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181128193636.254378-9-brendanhiggins@google.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 28, 2018 at 11:36:25AM -0800, Brendan Higgins wrote: > diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c > index cced829460427..bf90e678b3d71 100644 > --- a/arch/um/kernel/trap.c > +++ b/arch/um/kernel/trap.c > @@ -201,6 +201,12 @@ void segv_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs) > segv(*fi, UPT_IP(regs), UPT_IS_USER(regs), regs); > } > > +static void segv_run_catcher(jmp_buf *catcher, void *fault_addr) > +{ > + current->thread.fault_addr = fault_addr; > + UML_LONGJMP(catcher, 1); > +} > + > /* > * We give a *copy* of the faultinfo in the regs to segv. > * This must be done, since nesting SEGVs could overwrite > @@ -219,7 +225,10 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user, > if (!is_user && regs) > current->thread.segv_regs = container_of(regs, struct pt_regs, regs); > > - if (!is_user && (address >= start_vm) && (address < end_vm)) { > + catcher = current->thread.fault_catcher; This and.. > + if (catcher && current->thread.is_running_test) > + segv_run_catcher(catcher, (void *) address); > + else if (!is_user && (address >= start_vm) && (address < end_vm)) { > flush_tlb_kernel_vm(); > goto out; > } *not this* > @@ -246,12 +255,10 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user, > address = 0; > } > > - catcher = current->thread.fault_catcher; > if (!err) > goto out; > else if (catcher != NULL) { > - current->thread.fault_addr = (void *) address; > - UML_LONGJMP(catcher, 1); > + segv_run_catcher(catcher, (void *) address); > } > else if (current->thread.fault_addr != NULL) > panic("fault_addr set but no fault catcher"); But with this seems one atomic change which should be submitted separately, its just a helper. Think it would make the actual change needed easier to review, ie, your needed changes would be smaller and clearer for what you need. Luis